Re: [PATCH 3/3] usb: dwc3: support two connectors sharing one HS data bus

[sashiko-bot@kernel.org]

> On some boards a single DWC3 controller drives two receptacles: the Super
> Speed pairs are wired to separate PHYs, while the High Speed data lines are
> muxed to whichever connector is in use.  Such a controller has to service
> two independent role-switch inputs, and the shared data path has to be
> moved before the controller is reinitialised for the requested role.
> 
> Register one usb_role_switch per connector endpoint described by
> "port-select-gpios" and the per-endpoint "mux-state" property.  Requests
> from the two switches are serialised by the mux lock, the oldest pending
> request wins, and the port-select GPIO is only changed once the previous
> host or gadget instance has been torn down, which is where
> __dwc3_set_mode() runs.  A same-role request that moves the data path to
> the other connector reinitialises the controller as well and starts it
> from the same SUSPHY state as a role change.
> 
> [ ... ]
> 
> While the two-connector mux owns role selection, the debugfs "mode" write
> used to force a specific role is refused instead of racing with it.
> 
> Signed-off-by: Qianhui Xu <xiaqinghuan@mail.ustc.edu.cn>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261106112811.963923-1-xiaqinghuan@mail.ustc.edu.cn?part=3